Dialkylphenol sulfate-sulfonate

ABSTRACT

A detergent active material of the formula IN WHICH R and R&#39;&#39; are substantially linear alkyl groups of from about 8 to 22 carbon atoms and X is H or a water-soluble saltforming cation and the sum of the carbon atoms in R and R&#39;&#39; is from 18 to 40 carbon atoms, preferably 22 to 30 carbon atoms.   D R A W I N G

States Patent 1 ouse et al.

111 3,821,272 1451 June 28,1974

[ DIALKYLPHENOL SULFATE-SULFONATE [73] Assignee: Chevron Research Company, San

Francisco, Calif.

22 Filed: Aug. 2, 1971 21 Appl. No.: 168,477

152 u.s.c1.l..-. 260/457,252/551252/1310. 1. 252/1310. 6, 252/010. 14, 260/DlG. 9, 8/137 [58] Field ofSearch .L 260/457 {56] 1 References Cited- 2/1938 Bruson.... 260/457 X Primary Examinerlseon Zitver Assistant. Examiner-Norman Morgenstern Attorney, 'Agent, or FirmG. F. Magdeburger; John Stoner, Jr.

[ ABSTRACT A detergent active material of the formula 7 7 osoix i R s 08X in which R and R are substantially linear alkyl groups of from about 8 to 22 carbon atoms and X is H or a water-soluble saltforming cation and the sum of the carbon atoms' in R and/R is from 18 to .40 carbon atoms, preferably 22 to 30 carbon atoms.

I 4 Claims, No Drawings I DIALKYLPHENOL SULFATE-SULFONATE BACKGROUND OF THE INVENTION This invention is concerned with novel linear dialkylphenol sulfate-sulfonate compounds which are effective in detergent applications as detergent actives.

nonbiodegradability.

However, the above-mentioned surface-active materials are inadequate in terms of soil removal in the absence of phosphate builders. Increasing evidence appears to indicate that phosphates contribute to the growth of algae in the nations streams and lakes. This algae growth poses a serious pollution threat to the maintenance of clear, good domestic water supplies.

Consequently, there has developed a need for detergent active materials which will function successfully in the absence of phosphate builders. Recently, certain non-phosphate builders materials have been proposed as replacements for the phosphates. Thus, materials such as the polysodium salts of nitrilotriacetic acid, ethylene diamine tetraacetic acid, copolymers of ethylene and maleic acid, and similar polycarboxylic materials have been proposed as builders. These materials, however, when employed with conventional detergent actives such as LAS, have, for one reason or another, not proved to be quite as satisfactory as phosphates in detergent formulations. For example, some of the materials have proven to be insufficiently biodegradable to meet present and anticipated requirements.

It is therefore desirable to provide compounds which are effective as detergent active materials in theabsence of phosphate builders and are sufficiently biodegradable that their use does not contribute foam to the water supply.

In addition, in the past, with heavy duty detergents, it has been thought that to achieve good soil removal it was necessary to maintain a high pH in washing solutions. This concept, which began with the strongly alkaline laundry soaps, has continued to the present day LAS-phosphate combinations which are in widespread use in heavy duty detergent formulations. One apparent reason for this is that the alkylbenzene sulfonate detergents are not effective in heavy duty detergent formulations in the absence of a builder. The phosphate builders, for example, must be employed at a pH greater than 9 to be effective, and even the newer builders such as sodium nitriloacetate have a pH of about 9 in solution. The advantages to be gained with heavy duty detergents which may be employed at neutral pH are many. Deleterious effects from skin-contact are lessened. Enzyme-type soil looseners may be more easily combined in neutral solutions. Injury to fabrics is minimized. It is, therefore, desirable to provide detergent active materials which, in addition to the previously mentioned non-polluting characteristics, achieve their maximum detergency at or near neutral pH.

The formulation of liquid heavy duty detergent compositions achieves many desirable results. They are easy to package and measure, and their use opens the 2 possibility of automatic dispensing in washing machines. However, in the past it has been impracticable to formulate heavy duty detergents in liquid form because of the insufficient solubility of the inorganic in gredients (phosphate builders, etc.) required for heavy duty applications and the high cost of organic substitutes for such inorganic ingredients. It is therefore highly desirable to provide detergent active materials having good water solubility and which, because of their excellent detergency without builders, can be formulated into effective, reasonably priced, heavy duty liquid detergent formulations.

SUMMARY OF THE INVENTION Heavy duty detergent materials are provided which comprise alkylphenol sulfate-sulfonates of the formula (l)SOzX in which R and R are substantially linear alkyl groups of from about 8 to 22 carbon atoms and X is H or a water-soluble salt-forming cation and the sum of the carbon atoms in R and R is from 18 to 40 carbon atoms, preferably 22 to 30 carbon atoms.

The compounds of this invention do not require the presence of a builder to achieve good heavy duty detergency and are effective over a broad pH range. Further, the compounds may be easily compounded into effective liquid heavy duty formulations because ofthe substantial solubility of the compounds in water and because of the lack of need for large adjunctive portions of inorganic materials such as builders.

DESCRIPTION OF PREFERRED EMBODIMENTS The salt-forming cation X may be any of numerous materials such as alkali metal, alkaline earth metal, ammonium, or various organic cations. Examples of suitable organic cations include nitrogen-containing organic cations such as diethanol-ammonium and triethanolammonium cations. The alkali metal cations are preferred, and sodium ions are particularly preferred.

The alkyl groups represented by R and R are, as previously noted, substantially linear, although the presence of a random methyl radical upon the linear chain, for example, may not adversely affect the performance of the compounds. Alkyl radicals representative of R include octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, and docosyl. The preferred compounds will have a total of from about 22 to 30 carbon atoms.

The dialkylphenols which are suitable for the preparation of the compounds of this invention are prepared by conventional techniques. Such techniques include thermal and catalytic alkylation of phenol with olefins, alcohols and haloparaffins. Catalytic methods include the use of catalysts such as aluminum,.aluminum chloride, zinc chloride, etc., and various other acid catalysts and clay catalysts.

The alkyl groups are generally derived from alcohols, olefins, or haloparaffins. The position of the attachment of the aromatic nucleus on the alkyl chain may be at any point. With alpha olefins the predominant point of attachment of the alkylation product will be nearend attachment--that is, either at the l, 2 or 3, but principally at the 2 position of the chain. On the other hand, with an isomerized mixture of olefins or olefins derived from haloparaffins which have, in turn, been produced by halogenation of paraffins, the position of the double bond will be generally essentially random on the chain, and thus the corresponding aromatic nucleus attachment will be essentially random.

The sulfonation and sulfation of the dialkylphenols to produce the compounds of this invention is accomplished by reacting the dialkylphenol with a sulfonating agent capable of l) converting the aromatic hydroxyl radical to a sulfate and (2) forming a ring-substituted -SO H under conditions such that the reaction product contains both an OSO H and an SO H radical attached to the aromatic nucleus. The preferred sulfonating agent satisfying these reaction prerequisites is sulfur trioxide. The sulfur trioxide may be employed in mixtures with an appropriate liquid solvent such as a chlorinated hydrocarbon or liquid S The dialkylphenol sulfate-sulfonate compounds of this invention thus are suitably preferred by the reaction of a dialkylphenol with sulfur trioxide. The reaction is carried out in an anhydrous inert solvent such as the chlorinated hydrocarbons, e.g., dichloroethane. The quantity of sulfur trioxide to be used should equal or exceed 2 moles per mole of dialkylphenol for 100 percent conversion of the latter. Mole ratios of $0 to dialkylphenol as low as 3:1 may be employed, but preferably the ratio is in the range of 8:1 to 10:1. At mole ratios below 2:1, some of the desired dialkylphenol sulfate-sulfonate will be formed, but depending on the mole ratio used, substantial amounts of mono sulfonated material will be formed. Reaction temperatures are generally in the range of l0 to 10C, preferably about 5 to 0C. dialkylphenol dissolved in the solvent is cooled to the reaction temperature and then S0 dissolved in the same solvent is added. The reaction is exothermic, and cooling means must be employed to keep the temperature within the'desired range. The

rate of addition of S0 is such that the cooling means can hold this temperature. Thus the time required for reaction varies as to efficiency of cooling, size of reaction. mass, etc., but generally the addition will be complete within 10 to 120 minutes for small sized batches. Continuous procedure is preferred for large batches. In continuous processing, the reactants, dissolved in an appropriate solvent and cooled to reaction temperature, are chargedto a cooled tubular reactor, wherein the average residence time is only a few minutes or less.

After sulfonation, the reaction product may be neutralized with a water-soluble, salt-forming cationic neutralizing agent, usually a metal oxide or hydroxide, and more preferably an alkaline earth metal or alkali metal hydroxide. The alkali metal hydroxides are preferred, and sodium hydroxide is most preferred. In addition to the inorganic bases described above, the neutralizing agent may be any .of various organic bases. Sufficient base is added to neutralize both acid sites and the excess S0 The final pH of the neutralized mixture should be above 7, and pH values within the range of 8 to 10 are satisfactory.

Following neutralization, the inert organic solvent is removed for reuse. This may be done by phase separation, or preferably by distillation. The organic solvent free material comprises an aqueous solution of the organic surface active materials and any inorganic salt, such as sodium sulfate. The neutralized product, which will contain a substantial quantity of water and from 1 to 4 parts of a normally inorganic sulfate from the neutralization of excess S0 (e.g., Na SOi), may be used, as is, in combination with conventional detergent additives to formulate liquid heavy duty detergents. Alternatively, water may be removed in any quantity of completedryness by conventional concentration techniques such as evaporation, distillation, drum drying,

etc., to yield a concentrated, a slurry, or a solid which may then be blended to form a heavy duty detergent.

The solid product isolated as described above may be desalted by the usual procedures as used in the alkylbenzene sulfonate art. In this method the solid material is mixed with about a /30 alcohol/water solution. The insoluble inorganic sulfate is removed by filtration, and the organic surfactant may be used as such or isolated by evaporation of the solvent. The liquid concentrates and slurries may be treated in similar fashion with allowance made for the quantity of water already present. These desalting procedures give a detergent product that is essentially free of inorganic salt.

The following examples describe the preparation of the compounds of this invention.

EXAMPLE 1 Preparation of Didodecylphenol Sulfate-Sulfonate To a 20 ml. reaction vessel fitted with a septum, drying tube, thermometer, and a magnetic stirring bar, was charged 1.0 g. (0.00289 mols) of didodecylphenol. A 10 ml. portion of dry 1,2-dichloroethane was charged to the reaction flask. The solution was flushed with nitrogen and stirring was begun. The solution was cooled to 10C in an ice-acetone bath.

A solution of 1.0 ml anhydrous sulfur trioxide (1.9 g, 0.0237 mols) in 5 ml. of dry 1,2-dichloroethane was cooled to about 0C. The solution was injected into the reaction solution with a syringe at such a rate as to maintain the reaction temperature at about 0C. After the addition was complete, the cooling bath was removed, and the reaction mixture was allowed to warm to room temperature over a period of about l5 minutes. It was then added to 50 ml. of 0.5 N NaOH solution and titrated to a pH of about 10 with additional 0.5 N NaOH. The mixture was then placed upon a rotary evaporator, and the organic'solvent wa removed under vacuum at 2530C. The remaining water solution was diluted to 500 ml. and titrated by a standard Hyamine procedure* giving about a percent yield of didodecylphenol sulfate-solfonate. Dilute acid hydrolysis followed by Hyamine titration showed that the primary product contained both sulfate and sulfonate groups insubstantially equal amounts; that is, it was a dialkylphenol sulfate-sulfonate.

*See method of House and Darragh, Anal. Chem, 26, 1492 (1954).

An infrared spectrum of the product showed strong adsorption in the 1,020-1070 cm and in the l,200l ,280 cm regions.

EXAMPLE 2 sulfur trioxide. Analysis was by the method shown in Example 1-.

The compounds of this invention are useful as heavy duty detergent actives. In the past, heavy duty detergent formulations useful for removing soil from textiles have comprised an organic surfactant (detergent) and 'an inorganic phosphate builder; the phosphate being present by weight, in an amount of from one to four times that of the detergent. The compounds of the present invention are excellent soil removers without the aid of any phosphate builder. That is, the compounds of this invention satisfy all need for both organic surfactant and builder in the final heavy duty detergent formulation. One way that this may be accomplished is by preparing a mixture of the sulfate-sulfonate materials of the instant invention and an inert material, e.g., water, sodium sulfate, sodium carbonate, etc. Such mixtures may contain any amount of sulfate-sulfonate in excess of about percent, preferably percent or more. One useful composition comprises from 30 to 50 percent sulfate-sulfonate and the remainder, sodium sulfate. Many other combinations make useful formulations and may be either liquid solutions or particulate solids.

As heavy duty detergents, it is contemplated that the dialkylphenol sulfate-sulfonate compounds will be used in wash water at concentrations of about 0.01 percent to about 0.10 percent. This is within the same range of concentrations as are employed with the present day commercial detergents. In other words, the soil removal properties of the present compounds are essentially equivalent to the soil removal properties of an equal amount of the current commercial surfactant combined with at least an equal amount of phosphate.

as percent soil removal. Because of variations in degree and type of soiling, in water and in cloth, and other unknown variables, the art has developed the method of using relative detergency ratings for comparing detergent effectiveness.

The relative detergency ratings are obtained by comparing and correlating the percent soil removal results from solutions containing the detergents being tested with the results from two defined standard solutions. The two standard solutions are selected to represent a detergent system exhibiting relatively high detersive characteristics and a system exhibiting relatively low detersive characteristics. The systems are assigned detergency ratings of 6.3 and 2.2, respectively.

By washing portions of each soiled cloth with the standardized solutions, as well as with two test solutions, the results can be accurately correlated. The two standard solutions are identical in formulation but are employed at different hardnesses.

Standard Solution Formulation Ingredient Weight Z Linear Alkylbenzene sulfonate (LAS) 25 Sodium triphosphate 40 Water 8 Sodium sulfate 19 Sodium silicate 7 'Carboxymethylcellulose l The standard exhibiting high detersive characteristics (Control 8) is prepared by dissolving the above formulation 1.0 g.) in one liter of 50 ppm hard water (calculated as two-thirds calcium carbonate and one-third magnesium carbonate). The low detersive standard (Control A) contained the formulation (1.0 g.) dissolved in one liter of ppm water (same basis).

A miniature laboratory washer is so constructed that four different solutions can be used to wash different parts of the same swatch. This arrangement ensures that all four solutionsare working on identical soil (natural facial soil). Relative detergency ratings (RDRs) are calculated from soil removals (SRs) according to the equation:

RDR Test RControl A/% Control B Control A A further refinement in the determination of relative detergency ratings was developed. In this method, instead of employing two standard formulations, one of the formulations used as one of the four test solutions had a known relative detergency rating (RDR) which has been determined by the above formula. Relative detergency ratings of the other three formulations were then determined by comparing the percent soil removal (SR) of these formulations with that of the known formulation.

Detergency results obtained on a variety of the subject compounds are given in the following table. Each value shown is the average of at least four tests. For comparison, the detergency rating is given for a linear alkylbenzene sulfonate (LAS) (having from ll to 14 carbon straight chain alkyl groups) both with and without phosphate builder.

Each formulation 'tested comprised 25 weight percent of the test material along with 1% carboxymethylcellulose, 7% sodium silicate, 8% water, and 59% sodium sulfate. The LAS comparison formulations was prepared in the same way except that in Test 2 40% of the sodium sulfate was replaced by an equal amount of sodium tripolyphosphate and only 20% of LAS was used. The formulations were tested at a concentration in water of 0. 15 weight percent. This concentration was chosen because it is typical of household use. The test results were obtained at a pH of 7, except for the two LAS examples, which were run at a pH of 9 (without phosphate) adn 10 (with phosphate).

TABLE DETERGENT EFFECTWENESS OF LINEAR ALKYLPHENOL SULFATBSULFONATES Relative Detergency Ratings (at OTIS weight percent concentration) A mixture of dinonyl-. didecyL, and nonyldecyl-phcnol sulfate sulfonate.

These data show that the dialkylphenol sulfatesulfonates of this invention have a minimum of 22 alkyl carbons are superior to phosphate-free LAS and approach phosphate-built LAS in detergency.

The dialkylphenol sulfate-sulfonates may be employed in combination with other detergent active materials. They are particularly effective with other dianionic materials, examples of which include linear alkyl and alkenyl disulfates and disulfonates. A particularly useful class of materials for use in detergent active combinations is that of linear 2-alkenyl or linear 2-alkyl 1,4-butane diol disulfates in which the alkenyl or alkyl groups contain from to carbon atoms. Another particularly effective class of materials are the alkylphenol disulfonates described in our previously mentioned copending patent application.

In employing the detergent active materials of this invention in detergent compositions, they may be formulated with additional compatible ingredients being optionally incorporated to enhance the detergent properties. Such materials may include but are not limited to anticorrosion, antiredeposition, bleaching and sequestering agents, and certain organic and inorganic alkali metal and alkaline earth metal salts such as inorganic sulfates, carbonates, or borates. Also nonphosphate builders may be included in the composition. Examples of these builders include the sodium salts of nitrilotriacetic acid, ethylene diamine tetraacetic acid, and ethylene-maleic acid copolymers, etc. Also small quantities of phosphate builders may be included in the compositions, although, of course, they are not neces-' sary for effective detergency.

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and-without limitation of the invention. It will be apparent to those skilled in the art that modifications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

We claim:

. 1. A detergent active material of the formula:

in which R and R are linear alkyl radicals of 8 to 22 carbon atoms and X is hydrogen, an alkaline-earth metal cation or an alkali metal cation and the sum of the carbon atoms in R and R is from 18 to 40.

2. The detergent active material of claim 1 in which the sum of the carbon atoms is R and R is 22 to 30.

3. The detergent active material of claim 1 in which X is an alkali metal cation.

4. The detergent active material of claim 3 in which Xissodium. 

2. The detergent active material of claim 1 in which the sum of the carbon atoms is R and R'' is 22 to
 30. 3. The detergent active material of claim 1 in which X is an alkali metal cation.
 4. The detergent active material of claim 3 in which X is sodium. 